The present invention relates to a moulded pulp fibre product. The present invention also relates to a method of forming a moulded pulp fibre product.
Moulded pulp fibre is well known for use in packaging products, and single use food and beverage service trays/containers, and transport products. When made from products that can be recycled or otherwise composted after the product's useful life, moulded pulp fibre products can be “sustainable”, which is a highly desirable characteristic. In addition, moulded pulp fibre products can be less expensive to produce than equivalent products made of plastics materials.
A widely-utilized process (hereinafter referred to as the “basic process”) for forming moulded pulp fibre products involves:
A modified process for forming moulded pulp fibre products is known as “thermoforming”. This process involves applying heat and pressure to the wet pulp pre-form instead of the baking step of the basic process. The application of heat and pressure is achieved using a toolset of two (or more) complementary moulds that are heated, and pushed together with the pre-form disposed in the moulds to compress the wet pulp pre-form.
Products that are formed exclusively from moulded pulp fibre have limited applicability. This is at least in part due to the manner in which the wet pulp pre-form is created from the initial slurry.
It is known to make moulded pulp fibre products suitable for some applications by applying other materials, most commonly plastic films, to dry pulp fibre products. The result of these mixed material products is that the dissimilarity of the materials prevents, or at least inhibits, recycling or composting of the product.
There is a need to address the above, and/or at least provide a useful alternative process.
There is provided a method of forming a moulded pulp fibre product, the method involving:
forming two or more pulp fibre pre-forms that each include at least one mating surface, each pre-form being made from a suspension of pulp fibres in liquid;
assembling the pulp fibre pre-forms into a set in which adjacent pulp fibre pre-forms have mating surfaces that are in contact with, or adjacent to one another; and
bonding the set of pulp fibre pre-forms to thereby form a pulp fibre laminate.
The step of bonding the set of pulp fibre pre-forms can involve applying at least one of heat and pressure to the assembled set of pulp fibre pre-forms.
The step of bonding the set of pulp fibre pre-forms can involve creating mechanical bonds between adjacent pulp fibre pre-forms in the set.
Preferably, each mating surface is non-planar.
In some embodiments, the pulp fibre laminate formed by the method is the moulded pulp fibre product. In some alternative embodiments, the method further involves one or more processing steps on the pulp fibre laminate that result in formation of the moulded pulp fibre product.
The method can involve forming the pulp fibre pre-forms that are to be adjacent one another in the set with mating surfaces that fully complement one another.
The method can alternatively involve forming the pulp fibre pre-forms that are to be adjacent one another in the set with mating surfaces that only partially complement one another, and at least one of the assembling and bonding steps involves deforming at least one of the first and second pulp fibre pre-forms. In some embodiments, the deformation of at least one of the first and second pulp fibre pre-forms substantially eliminates cavities between the pre-forms.
The method can further involve creating two or more suspensions of pulp fibres in liquid, at least one of the pulp fibre pre-forms being formed of a first of the suspensions, and at least one of the pulp fibre pre-forms being formed of a second of the suspensions, and
wherein:
the pulp fibres used in each of the first and second suspensions are selected to have differing characteristics,
the liquid components of the first and second suspensions have differing substances dissolved and/or dispersed within the respective liquid component,
the liquid component of the first suspension and/or the second suspension includes substances that are not present in the liquid component of the other suspension, and/or
the first and/or second suspension has additives that alter the visual appearance of the respective lamina in the moulded pulp fibre product.
In embodiments in which the liquid components of the first and second suspensions have differing substances dissolved and/or dispersed within the respective liquid component:
substances within at least one of the suspensions undergo a chemical reaction with one another and/or with the pulp fibre component of the respective suspension, such that the laminae in the moulded pulp fibre product have differing properties; and/or
substances within at least one of the suspensions bond with the pulp fibres as the respective suspension dries, and wherein in the moulded pulp fibre product the solutes in the respective lamina contribute to the laminae in the moulded pulp fibre product having differing properties.
Preferably, for each pulp fibre pre-form, the forming step involves:
applying the suspension to a porous mould portion to form a slurry deposit on the mould portion; and
extracting fluid from the slurry deposit through the porous mould portion to form the pulp fibre pre-form.
In at least some embodiments, the steps of extracting fluid are such that, when assembling the pulp fibre pre-forms into the set, at least one of the pulp fibre pre-forms has a residual moisture content.
For each pulp fibre pre-form, the step of extracting fluid from the slurry deposit can involve any one or more of:
applying suction to the porous mould portion to draw fluid from the deposited slurry;
compressing the slurry deposit between opposing surfaces of a toolset to thereby squeeze liquid from the deposited slurry; and
heating the slurry deposit to thereby cause at least some liquid within the slurry deposit to change to gas.
Preferably, in embodiments in which fluid is extracted by compressing the respective slurry deposit, the slurry deposit is compressed in a toolset that includes two moulds that each define a respective one of two opposing surfaces that are shaped specifically for the respective pulp fibre pre-form.
In certain embodiments, for each pulp fibre pre-form, the step of extracting fluid from the slurry deposit can involve:
providing a press that includes the respective toolset;
transferring the slurry deposit from the porous mould portion to the toolset; and
compressing the slurry deposit between opposing surfaces of a toolset to thereby squeeze liquid from the deposited slurry.
Each toolset can include one or more heating elements associated with at least one of the respective moulds, and the method further involves transferring heat from the toolset to the respective slurry deposit simultaneously with the compressing step.
Alternatively or additionally, one or both of the moulds has pores that open onto the respective one of the opposing surfaces, and the method further involves extracting fluid from the respective slurry deposit by suction via the pores in the moulds.
Heating the slurry deposit can alternatively or additionally involve any one or more of: directing heated air towards the slurry deposit, exposing the slurry deposit to radiant heat, heating the porous mould toolset, and directing microwave and/or ultrasound energy towards the slurry deposit.
It will be understood that for the purposes of this specification and the claims that follow, “directing microwave and/or ultrasound energy towards the slurry deposit” will be understood to include putting a slurry deposit in an environment in which the slurry deposit is exposed to microwave and/or ultrasound energy, and passing a slurry deposit through an environment in which the slurry deposit is exposed to microwave and/or ultrasound energy.
In certain embodiments, for each pulp fibre pre-form, the step of extracting fluid from the respective slurry deposit can involve positioning a conformable material on the surface of that slurry deposit such that the slurry deposit is between the porous mould portion and the conformable material, and, when the conformable material is in contact with the slurry deposit, applying a pressure differential across the slurry deposit so as to draw the conformable material towards the porous mould portion and thereby squeeze the slurry deposit between the conformable material and the porous mould portion. A pressure differential across the slurry deposit may be achieved by application of suction to the porous mould portion, and/or application of positive pressure to the conformable material.
In some embodiments, the porous mould portion for each pulp fibre pre-form has a mould surface that defines a surface of the respective pulp fibre pre-form. In some embodiments, the surface of the pulp fibre pre-form that is defined by the mould surface corresponds with the respective mating surface of the pulp fibre pre-form. Alternatively, the mating surface of the respective pulp fibre pre-form is opposite to the surface that is defined by the corresponding mould surface.
The method can additionally involve incorporating one or more interstitial layers between two adjacent pulp fibre pre-forms in the set, wherein each interstitial layer is formed of material that has not been pulped. In some examples, the interstitial layer can have a shaped form corresponding with at least one surface that at least partially corresponds with one of the mating surfaces. Alternatively, the interstitial layer is formed in situ on one of the pulp fibre pre-forms. The material of the interstitial layer may include fibres. In some embodiments, the fibres are interconnected to distribute tensile stress from the pulp fibre through the interstitial layer in the pulp fibre laminate.
In some embodiments, the interstitial layers can be inserted between pulp fibre pre-forms prior to the assembling step. Alternatively, the interstitial layers can be inserted between pulp fibre pre-forms during the assembling step.
Some embodiments of the method can also involve applying one or more curable materials to at least one of the mating surfaces prior to the assembling step, the curable materials operating to form chemical bonds between adjacent pulp fibre pre-forms.
The curable material can be an adhesive that is applied to the respective mating surface. In some embodiments, the curable materials can include reactants that are applied to mating surfaces such that during the assembling and/or bonding steps the reactants are brought into contact with one another and undergo a chemical reaction, thereby curing and forming bonds between adjacent pulp fibre pre-forms.
In certain embodiments, the forming step for at least two adjacent pulp fibre pre-forms in the set involves forming a second of the adjacent pulp fibre pre-forms concurrently with the step of assembling the second of the adjacent pulp pre-forms with respect to the first of the adjacent pulp pre-forms.
There is provided a method of forming a moulded pulp fibre product, the method involving:
forming a first pulp fibre pre-form from a suspension of pulp fibres in liquid, the first pulp fibre pre-form including a first mating surface;
forming a second pulp fibre pre-form from a suspension of pulp fibres in liquid, the second pulp fibre pre-form including a second mating surface;
assembling the second pulp fibre pre-form with respect to the first pulp fibre pre-form, such that at least part of the first mating surface is in contact with, or adjacent to the second mating surface;
bonding the first and second pulp fibre pre-forms to one another, thereby forming a pulp fibre laminate.
The step of bonding the set of pulp fibre pre-forms can involve applying at least one of heat and pressure to the assembled first and second pulp fibre pre-forms.
The step of bonding the set of pulp fibre pre-forms can involve creating mechanical bonds between the first and second pulp fibre pre-forms.
Preferably, each mating surface is non-planar.
In some embodiments, the pulp fibre laminate formed by the method is the moulded pulp fibre product. In some alternative embodiments, the method further involves one or more processing steps on the pulp fibre laminate that result in formation of the moulded pulp fibre product.
The method can involve forming the first and second pulp fibre pre-forms such that the first and second mating surfaces fully complement one another.
The method can alternatively involve forming the first and second pulp fibre pre-forms with first and second mating surfaces that only partially complement one another, and at least one of the assembling and bonding steps involves deforming at least one of the first and second pulp fibre pre-forms. In some embodiments, the deformation of at least one of the first and second pulp fibre pre-forms substantially eliminates cavities between the pre-forms.
The assembling step can additionally involve incorporating one or more interstitial layers between the first and second pulp fibre pre-forms, wherein each interstitial layer is formed of material that has not been pulped. In some examples, the interstitial layer can have a shaped form corresponding with at least one surface that at least partially corresponds with one of the mating surfaces. Alternatively, the interstitial layer is formed in situ on one of the pulp fibre pre-forms. The material of the interstitial layer may include fibres. In some embodiments, the fibres are interconnected to distribute tensile stress from the pulp fibre through the interstitial layer in the pulp fibre laminate.
In some embodiments, the interstitial layers can be inserted between pulp fibre pre-forms prior to the assembling step. Alternatively, the interstitial layers can be inserted between pulp fibre pre-forms during the assembling step.
Some embodiments of the method can also involve applying one or more curable materials to at least one of the first and second mating surfaces prior to the assembling step, the curable materials operating to form chemical bonds between adjacent pulp fibre pre-forms.
The curable material can be an adhesive that is applied to the respective mating surface. In some embodiments, the curable materials can include reactants that are applied to the first and second mating surfaces such that during the assembling and/or bonding steps the reactants are brought into contact with one another and undergo a chemical reaction, thereby curing and forming bonds between the first and second pulp fibre pre-forms.
The method can further involve:
creating a first suspension of pulp fibres in liquid from which the first pulp fibre pre-form is formed, and
creating a second suspension of pulp fibres in liquid from which the second pulp fibre pre-form is formed,
wherein:
the pulp fibres used in each of the first and second suspensions are selected to have differing characteristics,
the liquid components of the first and second suspensions have differing substances dissolved and/or dispersed within the respective liquid component,
the liquid component of the first suspension and/or the second suspension includes substances that are not present in the liquid component of the other suspension, and/or
the first and/or second suspension has additives that alter the visual appearance of the respective lamina in the moulded pulp fibre product.
In embodiments in which the liquid components of the first and second suspensions have differing substances dissolved and/or dispersed within the respective liquid component:
substances within at least one of the suspensions undergo a chemical reaction with one another and/or with the pulp fibre component of the respective suspension, such that the laminae in the moulded pulp fibre product have differing properties; and/or
substances within at least one of the suspensions bond with the pulp fibres as the respective suspension dries, and wherein in the moulded pulp fibre product the solutes in the respective lamina contribute to the laminae in the moulded pulp fibre product have differing properties.
Preferably, the step of forming the first pulp fibre pre-form involves:
applying the first suspension to a first porous mould portion to form a first slurry deposit on the first mould portion; and
extracting fluid from the first slurry deposit through the first porous mould portion to form the first pulp fibre pre-form.
The step of extracting fluid from the first slurry deposit can involve any one or more of:
applying suction to the first porous mould portion to draw fluid from the deposited slurry;
compressing the first slurry deposit between opposing surfaces of a first toolset to thereby squeeze liquid from the deposited slurry; and
heating the slurry deposit to thereby cause liquid within the slurry deposit to change to gas.
In certain embodiments, the step of extracting fluid from the first slurry deposit can involve:
providing a press that includes the first toolset;
transferring the first slurry deposit from the first porous mould portion to the first toolset; and
compressing the first slurry deposit between opposing surfaces of a first toolset to thereby squeeze liquid from the deposited slurry.
The first toolset can include two moulds that each define a respective one of the opposing surfaces, and one or more heating elements associated with at least one of the moulds, and the method further involves transferring heat from the toolset to the first slurry deposit simultaneously with the compressing step.
Alternatively or additionally, one or both of the moulds has pores that open onto the respective one of the opposing surfaces, and the method further involves extracting fluid from the first slurry deposit by suction via the pores in the moulds.
Heating the first slurry deposit can alternatively or additionally involve any one or more of: directing heated air towards the first slurry deposit, exposing the first slurry deposit to radiant heat, heating the porous mould toolset, and directing microwave and/or ultrasound energy towards the first slurry deposit.
In certain embodiments, the step of extracting fluid from the first slurry deposit can involve positioning a conformable material on the surface of the first slurry deposit such that the first slurry deposit is between the first porous mould portion and the conformable material, and, when the conformable material is in contact with the first slurry deposit, applying a pressure differential across the slurry deposit so as to draw the conformable material towards the first porous mould portion and thereby squeeze the first slurry deposit between the conformable material and the first porous mould portion.
In some embodiments, the first porous mould portion has a mould surface that defines a surface of the first pulp fibre pre-form. In some embodiments, the surface of the first pulp fibre pre-form that is defined by the mould surface corresponds with the first mating surface. Alternatively, the mating surface of the first pulp fibre pre-form is opposite to the surface that is defined by the mould surface.
Preferably, the step of forming the second pulp fibre pre-form involves:
applying the second suspension to a second porous mould portion to form a second slurry deposit on the second mould portion; and
extracting fluid from the second slurry deposit through the second porous mould portion to form the second pulp fibre pre-form.
The step of extracting fluid from the second slurry deposit can involve any one or more of:
applying suction to the second porous mould portion to draw fluid from the deposited slurry;
compressing the second slurry deposit between opposing surfaces of a second toolset to thereby squeeze liquid from the deposited slurry; and
heating the slurry deposit to thereby cause liquid within the slurry deposit to change to gas.
In certain embodiments, the step of extracting fluid from the second slurry deposit can involve:
providing a press that includes the second toolset;
transferring the second slurry deposit from the second porous mould portion to the second toolset; and
compressing the second slurry deposit between opposing surfaces of a second toolset to thereby squeeze liquid from the deposited slurry.
The second toolset can include two moulds that each define a respective one of the opposing surfaces, and one or more heating elements associated with at least one of the moulds, and the method further involves transferring heat from the toolset to the second slurry deposit simultaneously with the compressing step.
Alternatively or additionally, one or both of the moulds has pores that open onto the respective one of the opposing surfaces, and the method further involves extracting fluid from the second slurry deposit by suction via the pores in the moulds.
Heating the second slurry deposit can alternatively or additionally involve any one or more of: directing heated air towards the second slurry deposit, exposing the second slurry deposit to radiant heat, heating the second porous mould portion, and directing microwave and/or ultrasound energy towards the second slurry deposit.
In certain embodiments, the step of extracting fluid from the second slurry deposit can involve positioning a conformable material on the surface of the second slurry deposit such that the second slurry deposit is between the second porous mould portion and the conformable material, and, when the conformable material is in contact with the second slurry deposit, applying suction to the second porous mould portion to draw the conformable material towards the second porous mould portion and thereby squeeze the second slurry deposit between the conformable material and the second porous mould portion.
In some embodiments, the second porous mould portion has a mould surface that defines a surface of the second pulp fibre pre-form. In some embodiments, the surface of the second pulp fibre pre-form that is defined by the mould surface corresponds with the second mating surface. Alternatively, the mating surface of the second pulp fibre pre-form is opposite to the surface that is defined by the mould surface.
In certain embodiments, the steps of forming the second pulp fibre pre-form occurs concurrently with the step of assembling the second pulp pre-form with respect to the first pulp pre-form.
There is also provided a moulded pulp fibre product comprising:
two or more lamina formed of dried pulp fibre materials that are assembled and bonded to form a pulp fibre laminate,
wherein, in the moulded pulp fibre product:
at least two of the laminae have pulp fibres with differing characteristics;
at least one of the lamina includes substances within the lamina that are bonded with the respective pulp fibres, the substances:
having been dissolved and/or dispersed within the liquid component of the suspension from which the lamina is formed, and
causing the respective lamina to have different properties to at least one other lamina in the moulded pulp fibre product; and/or
at least one of the lamina is formed from a suspension that includes additives causing the respective lamina to have a visually different appearance to at least one other lamina in the moulded pulp fibre product.
In order that the invention may be more easily understood, embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:
In the method 10 illustrated in
In assembling step 16, the two pulp fibre pre-forms are assembled, one onto/over the other—“Assembly Station” in
Further, bonding step 18 in this example involves application of at least pressure to the assembled first and second pulp fibre pre-forms in a press—“Press Station 3” in
It will be appreciated that the bonding step 18 is likely to involve deformation of the first and second pulp fibre pre-forms 20, 22. This is particularly likely to occur where the bonding step 18 involves applying mechanical pressure to the pre-forms 20, 22, such as between opposing surfaces of the toolset of a press. The extent of deformation will at least partly depend on the initial shapes of the pre-forms 20, 22 and the shapes of the tools within the press.
As will be apparent from
The method 10 has the advantage that the pre-forms 20, 22 can be formed from suspensions of pulp fibres in liquids having different characteristics that give rise to differing characteristics in the laminae of the pulp fibre laminate 44 produced by the method 10. Consequently, the pulp fibre laminate 44 (and thus also the moulded pulp fibre product) can have the benefit of those differing characteristics in its laminae.
The production time for a moulded pulp fibre product is at least in part a function of the wall thickness of that product. Further, that function relates the production time to the wall thickness, involving an exponential of the wall thickness with the exponent being positive and greater than 1. Thus, the method 10 can also provide the advantage of enabling a faster production rate for a moulded pulp fibre product that is a laminate of two or more pulp pre-forms and has a nominal wall thickness, when compared with a moulded pulp fibre product having the same nominal wall thickness and being formed from a single pulp pre-form.
By way of example, the pulp fibre laminate 44 shown in
The first and second suspensions can be formed of differing constituent materials. To this end and depending on the desired properties of the respective lamina, the first and second suspensions can be formed of differing pulp fibres, differing liquid components, and/or additives. In this way, the lamina formed by the first and second suspensions can have different functional and/or aesthetic properties. Alternatively or additionally, the suspensions of the respective lamina may perform differently during the applying sub-steps 12a, 14a and/or the extracting sub-steps 12b, 14b.
In one example, the pulp fibre laminate 44 can have the first pulp pre-form 20 formed from a first suspension that includes cellulose fibres in a liquid water and polyvinyl alcohol (PVA) blend, and the second pulp pre-form 22 formed from a second suspension that includes bagasse fibres in a liquid water and starch blend. Further, the fibres of each of the first and second suspensions can be processed to have differing diameters and/or lengths. In this way, the properties of each of the first and second pulp pre-forms 20, 22 make differing contributions to the overall properties of the pulp fibre laminate 44.
Further, it may be desirable for the pulp fibre laminate 44 to visually indicate the particular ground coffee aliquot that will ultimately be stored within the bowl portion 48. To provide this visual indication, an additive, in the form of a coloured dyes or pigmented matter, within the second suspension will colour the second pulp pre-form 22 that is discernible externally of the pulp fibre laminate 44.
By way of example only, the second pulp pre-form 22 may include shredded coffee husk, which will ultimately be visible in the outer major surface 42 of the pulp fibre laminate 44. The visible coffee husk material includes pigments that assist consumers in identifying qualities, characteristics, etc. of the final moulded pulp fibre product.
It will be readily apparent from a comparison of
The pulp fibre laminate 144 has annular flange 146 that extends around the rim of a bowl portion 148. The annular flange 146 is formed of the bonded annular flanges 124, 134, and the bowl portion 148 is formed of the bonded bowl portions 126, 136. The above-described deformation of the first pulp pre-form during the bonding step 18 causes surfaces of bowl portion 126 to adopt a shape that generally corresponds with the second mating surface 138, having regard to the thickness of the lamina in the pulp fibre laminate 144 that is derived from the first pulp pre-form 120. Thus, the bonding step 18, while the outer major surface 142 of the second pulp fibre pre-form 122 is carried through to the pulp fibre laminate 144, the general shape of the second mating surface 138 is translated to the internal surface 140 of the bowl portion 148.
Embodiments of the method 10 in which the first and second mating surface only partially complement each other may be desirable where one or more of the pulp pre-forms has a high moisture content prior to the completion of the bonding step. In such instances, the high moisture content can result in uncontrolled deformation during the assembling step 16. It will be appreciated that retaining an interstitial cavity 150 (or multiple interstitial cavities) prior to the bonding step 18 can facilitate greater control in the wall thickness of the laminae in the final pulp fibre laminate.
In the method 210 illustrated in
Heating the first slurry deposit can involve any one or more of: directing heated air towards the second slurry deposit, exposing the first slurry deposit to radiant heat, heating the first porous mould portion, and directing microwave and/or ultrasound energy towards the first slurry deposit. By the selected heating action, the first slurry deposit is dried to form the first pulp pre-form as a “green part”.
In the method 310 illustrated in
In the method 410 illustrated in
In one example, the first pulp pre-form can be retained on the first porous mould portion, and the second suspension of pulp fibres in liquid is applied onto the exposed surface of the first pulp pre-form, thereby forming the second pulp fibre pre-form on the first pulp fibre pre-form.
In one example, step 452 may be achieved by process steps for forming a pre-form for a moulded pulp fibre product that are described and illustrated in the Applicant's International Patent Application PCT/AU2020/050039 (which claims priority from Australian Patent Application No. 2019900218), the disclosure of which is incorporated herein by reference.
In the embodiment of
The method 410 further involves step 418, in which the first and second pulp fibre pre-forms are bonded to one another, thereby forming a pulp fibre laminate. In this example, step 418 involves application of at least pressure to the assembled first and second pulp fibre pre-forms in a press—“Press Station” in
It will be apparent from
As with bonding step 18 (of the method 10), bonding step 518 of this method 510 involves application of at least pressure to the assembled first and second pulp fibre pre-forms in a press—“Post-Assembly Press Station” in
In the method 510 illustrated in
Method 610 differs from method 10 in that it includes an additional step 654 within forming step 612. Step 654 involves applying a curable materials to the first mating surface of the first pulp fibre pre-form prior to the assembling step, the curable materials operating to form chemical bonds between adjacent pulp fibre pre-forms.
In one example, a heat activated adhesive in a liquid form may be applied by a set of spray heads—“Spray Station” in
In another example, curable materials can be applied in step 654 that form a layer between the pulp fibre laminae of the pulp fibre laminate, the additional layer providing a barrier to gas or liquid propagating through the pulp fibre laminate. For instance, a liquid with highly refined fibres, such as highly refined cellulose fibres and/or cellulose nano-fibres, can be applied in a spray via the set of spray heads onto the slurry deposit of the first pulp pre-form. In this way, a chemical and/or nano-fibre interlayer can be formed between the laminae from the first and second pulp pre-forms. As will be appreciated, the interlayer in a pulp fibre laminate that is formed by this embodiment will not be part of a contact surface in the final pulp fibre laminate.
Bonding step 618 of this method 610 involves application of heat and pressure to the assembled first and second pulp fibre pre-forms in a press—“Press Station 3” in
The first pulp pre-form 720a has an annular flange 724a that extends around the rim of a bowl portion 726a. A first mating surface 728a is defined by the generally convex surface of the bowl portion 726a and the surface of the annular flange 724a that is contiguous with that convex surface. The bowl portion 726a has an internal surface 730a that defines an internal cavity 732a.
The second pulp pre-form 722a similarly has an annular flange 734a that extends around the rim of a bowl portion 736a. The second formed pulp pre-form 722a has a second mating surface 738a that, in this example, is defined by the generally concave surface of the bowl portion 736a and the upper surface of the annular flange 734a. The second pulp fibre pre-form 722a has an outer major surface 742a that is opposite the second mating surface 738a.
In this example, outer major surface 742a will become the external surface of the bowl of the final pulp fibre laminate. Further, internal surface 730a and internal cavity 732a will become the internal surface and cavity of the bowl of the final pulp fibre laminate.
The first and second pulp pre-forms 720a, 722a are shaped so that mating surfaces 728a, 738a only partially complement each other. As shown in enlarged Regions Xa and Ya of
As will be appreciated particularly from enlarged Region Xa of
During the bonding step 518 of the method 510 as applied to the first and second pulp pre-forms 720a, 722a, the side wall and base of the bowl portion 726a of the first pulp pre-form 720a will be deformed. To this end, the side wall and base of the bowl portion 726a will be displaced radially outwardly and longitudinally (with respect to the central axis of symmetry) to bring the first mating surface 726a to fully contact the second mating surface 736a. It will be appreciated that in practice it is likely that there will also be deformation of the side wall and base of the bowl portion 736a of the second pulp pre-form 722a, involving inward movement towards bowl portion 726a. In this way, the interstitial cavity 750a will be eliminated.
With respect to the example shown in
The bases of the bowl portions 726b, 736b are shaped such that the mating surfaces 728b, 738b complement each other. In particular, the base of bowl portion 726b includes a dimple formation 760b, and the base of bowl portion 736b also includes a dimple formation 762b.
Prior to bonding, the side walls of the bowl portions 726b, 736b are spaced from one another, such that an interstitial cavity 750b is formed therebetween. Further, the side wall of the bowl portion 726b of the first pulp pre-form 720b has a draft angle that is less than that of the side wall of the bowl portion 736b of the first pulp pre-form 722b. The width of the interstitial cavity 750b decreases in a direction away from the annular flanges 724b 734b.
It will be appreciated that the differing draft angles and complementing mating surfaces 728b, 738b within the base of the bowl portions 726b, 736b can provide the benefit of facilitating the assembling step 516. To this end, the first and second pulp pre-forms 720b, 722b can be brought into axial alignment during the assembling step 516, with the dimple formations 760b, 762b aiding in this alignment. The differing draft angles aiding in mitigating contact of the side walls of the bowl portions 726b, 736b with one another that may disrupt the fibres in the pre-forms.
It is also relevant to observe, particularly from Region Xb, that the diameter of the annular flange 724b of the first pulp pre-form 720b is smaller than that of the annular flange 734b of the second pulp pre-form 722b. Further, the first pulp pre-form 720b has a larger radius in its transition from the annular flange 724b to the bowl portion 726b, when compared with the corresponding features of the second pulp pre-form 722b.
During the bonding step 518 of the method 510 as applied to the first and second pulp pre-forms 720b, 722b, both the annular flange 724b and the side wall of the bowl portion 726b of the first pulp pre-form 720b will be deformed. To this end, the annular flange 724b and the side wall of the bowl portion 726b will be displaced radially outwardly (with respect to the central axis of symmetry) to bring the first mating surface 726b to fully contact the second mating surface 736b. It will be appreciated that in practice it is likely that there will also be deformation of the side wall of the bowl portion 736b of the second pulp pre-form 722b, involving inward movement towards bowl portion 726b. In this way, the interstitial cavity 750b will be eliminated.
With respect to the example shown in
The bases of the bowl portions 726c, 736c are shaped such that the mating surfaces 728c, 738c complement each other. In particular, the base of bowl portion 726c includes a dimple formation 760c, and the base of bowl portion 736c also includes a dimple formation 762c.
The first pulp pre-form 720c has a larger radius in its transition from the annular flange 724c to the bowl portion 726c, when compared with the corresponding features of the second pulp pre-form 722c. This difference is evident in the first and second pulp pre-forms 720c, 722c, as shown in enlarged Region Xc.
As particularly shown in enlarged Region Yc, the first pulp pre-form 720c has a smaller radius in its transition from the side wall to the base of the bowl portion 726c, when compared with the corresponding features of the second pulp pre-form 722c.
Prior to bonding, the side walls of the bowl portions 726c, 736c are spaced from one another, such that an interstitial cavity 750c is formed therebetween. The side wall of the bowl portion 726c of the first pulp pre-form 720c has a draft angle that is greater than that of the side wall of the bowl portion 736c of the first pulp pre-form 722c. Consequently, the separation of the first and second mating surfaces 728c, 738c within the side walls of the bowl portions 726c, 736c increases from the annular flanges 724c, 734c in a direction towards the bases. In other words, the interstitial cavity 750c is generally annular in shape, and the difference between the internal and external radii of the interstitial cavity increases from the annular flanges 724, 734 in a direction towards the bases.
It will be appreciated that the differing draft angles facilitate the insertion of the first pulp pre-form 720c into the internal cavity 742c of the second pulp pre-form 722c (during the assembling step 516). The complementing mating surfaces 728c, 738c within the annular flanges 724c, 734c and the base of the bowl portions 726c, 736c provide the benefit of facilitating axial alignment of the two pre-forms during the assembling step 516. To this end, the first and second pulp pre-forms 720c, 722c can be brought into axial alignment, whilst avoiding contact of the side walls of the bowl portions 726c, 736c with one another that disrupt the fibres in the pre-forms.
During the bonding step 518 of the method 510 as applied to the first and second pulp pre-forms 720c, 722c, the side wall of the bowl portion 726c of the first pulp pre-form 720c will be deformed. To this end, the side wall of the bowl portion 726c will be displaced radially outwardly (with respect to the central axis of symmetry) to bring the first mating surface 726c to fully contact the second mating surface 736c. It will be appreciated that in practice it is likely that there will also be deformation of the side wall of the bowl portion 736c of the second pulp pre-form 722c, involving inward movement towards bowl portion 726c. In this way, the interstitial cavity 750c will be eliminated.
In
Parts and features of each of the first and second pulp pre-forms 820, 822, and the pulp fibre laminate 844 that are the same or similar to parts and features of the first and second pulp pre-forms 20, 22, and the pulp fibre laminate 44 (illustrated in
In the method illustrated by
In the final pulp fibre laminate 844, the interstitial layer 880 is bonded within the pulp fibre materials. Consequently, load is transferred between the pulp fibre material and the material of the interstitial layer. The interstitial layer 880 distributes tensile and shear stress, such that the ability of the pulp fibre laminate 844 to retain its integrity when subjected to working loads is improved. To this end, the interstitial layer 880 can enable the pulp fibre laminate 844 to support positive pressures within the internal cavity 832 without rupturing. In this example, the inclusion of the interstitial layer 880 improves the ability of the pulp fibre laminate 880 to support hoop and longitudinal stresses generated by the positive internal pressure.
The interstitial layer 880 is preferably made of a non-synthetic material, so that the biodegradability and/or compostability of the pulp fibre laminate 844 is not compromised by the inclusion of the interstitial layer. In some examples, the interstitial layer 880 can include fibres made from plant material (such as linen, hemp, cotton, coir, bamboo etc.), animal protein-based fibres, and mineral fibre (such as mineral wool). The interstitial layer 880 can include filament fibres that are made artificially from biological processes. Further, the interstitial layer 880 can be a blend fibres from two or more sources.
In this example, the material of the interstitial layer 880 is an open weave material, which allows the pulp fibres in the first and second pulp pre-forms 820, 822 to form bonds that extend through the interstitial layer 880 during the bonding step of the method.
To facilitate the assembling step involving the first and second pulp pre-forms 820, 822 and the interstitial layer 880, the interstitial layer may have a shaped form that corresponds (at least partially) with one or both of the mating surfaces 828, 838. Alternatively or additionally, prior to the assembling step, the interstitial layer 880 can be soaked in liquid to facilitate the material conforming to the shape of the surfaces 828, 838.
Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.
Number | Date | Country | Kind |
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2019902722 | Jul 2019 | AU | national |
Filing Document | Filing Date | Country | Kind |
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PCT/AU2020/050776 | 7/30/2020 | WO |